Conflicting images

Posterior reversible encephalopathy syndrome in a postpartum hemorrhagic woman without hypertension: A case report

RATIONALE

Posterior reversible encephalopathy syndrome (PRES), which diagnosis is based on clinical symptoms and radiological features, is a neurotoxic disease characterized by a set of clinical manifestations, such as seizure, headache, visual, and/or consciousness disturbance. It is the first case of PRES followed by postpartum hemorrhage (PPH) without underlying disease.

PATIENT CONCERNS

A 37-year-old healthy woman had PPH after caesarean section. Six days after delivery, headache occurred suddenly, followed by episodes of clonus seizure.

DIAGNOSES

Brain computed tomography showed ischemic stroke. However, magnetic resonance imaging revealed characteristics consistent with PRES.

INTERVENTIONS

The patient received phenytoin for seizure control.

OUTCOMES

Seizure was under good control over the following days. Three months later, repeated magnetic resonance imaging showed complete remission.

LESSONS

PRES may be triggered by PPH and is not necessarily secondary to typical predisposing factors such as hypertension or pre/eclampsia. Hormone fluctuation, increased blood pressure variation, and massive blood transfusion may be contributed to the development of PRES in our case. Also, it is necessary to rule out those life-threatening diseases, such as cavernoma hemorrhage, cerebral venous thrombosis, and ischemic stroke before the diagnosis of PRES.

Prediction of Cerebral Hyperperfusion Syndrome with Velocity Blood Pressure Index

Background:

Cerebral hyperperfusion syndrome is an important complication of carotid endarterectomy (CEA). An >100% increase in middle cerebral artery velocity (MCAV) after CEA is used to predict the cerebral hyperperfusion syndrome (CHS) development, but the accuracy is limited. The increase in blood pressure (BP) after surgery is a risk factor of CHS, but no study uses it to predict CHS. This study was to create a more precise parameter for prediction of CHS by combined the increase of MCAV and BP after CEA.

Methods:

Systolic MCAV measured by transcranial Doppler and systematic BP were recorded preoperatively; 30 min postoperatively. The new parameter velocity BP index (VBI) was calculated from the postoperative increase ratios of MCAV and BP. The prediction powers of VBI and the increase ratio of MCAV (velocity ratio [VR]) were compared for predicting CHS occurrence.

Results:

Totally, 6/185 cases suffered CHS. The best-fit cut-off point of 2.0 for VBI was identified, which had 83.3% sensitivity, 98.3% specificity, 62.5% positive predictive value and 99.4% negative predictive value for CHS development. This result is significantly better than VR (33.3%, 97.2%, 28.6% and 97.8%). The area under the curve (AUC) of receiver operating characteristic: AUC_VBI= 0.981, 95% confidence interval [CI] 0.949–0.995; AUC_VR= 0.935, 95% CI 0.890–0.966, P = 0.02.

Conclusions:

The new parameter VBI can more accurately predict patients at risk of CHS after CEA. This observation needs to be validated by larger studies.

Cerebral hyperperfusion syndrome

Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy is characterised by ipsilateral headache, hypertension, seizures, and focal neurological deficits. If not treated properly it can result in severe brain oedema, intracerebral or subarachnoid haemorrhage, and death. Knowledge of CHS among physicians is limited. Most studies report incidences of CHS of 0-3% after carotid endarterectomy. CHS is most common in patients with increases of more than 100% in perfusion compared with baseline after carotid endarterectomy and is rare in patients with increases in perfusion less than 100% compared with baseline. The most important risk factors in CHS are diminished cerebrovascular reserve, postoperative hypertension, and hyperperfusion lasting more than several hours after carotid endarterectomy. Impaired autoregulation as a result of endothelial dysfunction mediated by generation of free oxygen radicals is implicated in the pathogenesis of CHS. Treatment strategies are directed towards regulation of blood pressure and limitation of rises in cerebral perfusion. Complete recovery happens in mild cases, but disability and death can occur in more severe cases. More information about CHS and early institution of adequate treatment are of paramount importance in order to prevent these potentially severe complications.

Postcarotid Endarterectomy Hyperperfusion or Reperfusion Syndrome

Background and Purpose— Hyperperfusion syndrome (HS) after carotid endarterectomy (CEA) has been related to impaired cerebrovascular autoregulation in a chronically hypoperfused hemisphere. Our aim was to provide new insight into the pathophysiology of the HS using magnetic resonance imaging (MRI) studies with diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI).

Methods— Five out of 388 consecutive patients presented 2 to 7 days after CEA, partial seizures (n=5), focal deficits (n=5), and intracerebral hemorrhage (n=3). In 4 patients, using sequential examinations, we identified vasogenic or cytotoxic edema by DWI; we assessed relative interhemispheric difference (RID) of cerebral blood flow (CBF) by PWI; and we measured middle cerebral artery mean flow velocities (MCA Vm) by transcranial Doppler (TCD).

Results— None of the patients presented pathological DWI hyperintensities, consistent with the absence of acute ischemia or cytotoxic edema. In 2 patients, we found an MRI pattern of reversible vasogenic edema similar to that observed in the posterior leukoencephalopathy syndrome. Middle cerebral artery (MCA) mean flow velocities (Vm) were not abnormally increased at any time. PWI documented a 20% to 44% RID of CBF in favor of the ipsilateral to CEA hemisphere.

Conclusions— HS can occur in the presence of moderate relative hyperperfusion of the ipsilateral hemisphere. MCA Vm values may not accurately reflect RID of CBF over the cortical convexity. We suggest that the hemodynamic pathogenetic mechanisms of the HS are more complicated than hitherto believed and that they may be more accurately described by the term “reperfusion syndrome.”

Seizures after carotid endarterectomy: hyperperfusion, dysautoregulation or hypertensive encephalopathy?

OBJECTIVES

Presentation, management and outcome following seizure after carotid endarterectomy (CEA). MATERIALS AND DESIGN: Prospective audit.

RESULTS

Eight patients (0.8%) suffered a seizure (three bilateral) <30 days following 949 CEAs. Seizure was not associated with age, gender or presentation. Seven were treated hypertensives but four had labile BP pre-operatively. Five had severe bilateral carotid disease and four had vertebral/subclavian stenoses. Six had a >50% drop in middle cerebral artery blood flow velocity (MCAV) with clamping. Only three had >100% increase in MCAV with flow restoration. Five required treatment for post-operative hypertension. Two suffered seizures <36 hrs of CEA, the remainder were at 3-8 days. All eight had significantly elevated blood pressure at onset of seizures. Four underwent immediate MCAV monitoring and each was elevated. Emergency CT scanning/autopsy showed normal scans (n = 3), white matter oedema (n = 3), oedema and diffuse haemorrhage (n = 1), intracranial haemorrhage (n = 1). Seven developed a post-ictal neurological deficit (stroke = 5, TIA = 2). Overall, two patients either died or suffered a disabling stroke.

CONCLUSIONS

Post-CEA seizure was associated with adverse outcome. Most were labile hypertensives with severe bilateral carotid/vertebral disease. MCAV changes suggested poor collateral recruitment, but no consistent pattern of early hyperperfusion emerged. It remains uncertain whether high MCAVs and severe hypertension after seizure onset are cause or effect. Clinicians treating these patients in acute medical units were generally unaware of the "post-CEA hyperperfusion syndrome" and tended to treat the hypertension less aggressively.

Mechanisms of intracerebral hemorrhage after carotid endarterectomy

OBJECT

Intracerebral hemorrhage (ICH) is an uncommon complication of carotid endarterectomy (CEA), and carries a high rate of mortality and morbidity. Traditionally, attention has been focused on the cerebral hyperperfusion syndrome (HPS) as the leading cause of ICH after CEA. Other mechanisms, such as a perioperative cerebral ischemic event, cerebral infarction, and use of postoperative anticoagulation therapy, may also be important.

METHODS

The authors performed a retrospective case control study to identify factors leading to ICH after CEA. Records of CEAs performed over the past 10 years at the Mayo Clinic were searched for occurrences of ICH within 30 days of the procedure. The relationship of ICH to known cerebrovascular risk factors, perioperative electroencephalographic studies, and 133Xe cerebral blood flow (CBF) studies was compared with that in a control group. Hyperperfusion was defined as hypertension with symptoms of either severe headache, seizures, or confusion, or a doubling of intraoperative CBF values. The clinical history and imaging of ischemic events and the ICH were carefully reviewed to determine the possible underlying mechanism(s). Twelve (0.4%) of 2747 patients who underwent CEAs suffered a postoperative ICH. A doubling of CBF values was found in five of eight cases in which CBF studies were performed, and occurred more commonly in the patients with ICH than in controls. Clinical symptoms of the HPS were less common (three cases). A perioperative cerebral ischemic event (four cases) and anticoagulation therapy (six cases) were other contributors to a subsequent ICH. Seven of the 12 patients with ICHs died and five achieved a moderate outcome.

CONCLUSIONS

An ICH following CEA is an unusual complication that occurs in the setting of hyperperfusion, perioperative cerebral ischemia, anticoagulation therapy, or multiple mechanisms. Identification of CBF doubling at surgery may assist in identifying patients at risk for ICH following CEA.

Epileptic seizures attributed to cerebral hyperperfusion after percutaneous transluminal angioplasty and stenting of the internal carotid artery

Cerebral hyperperfusion syndrome as a complication of carotid endarterectomy (CEA) has been widely reported in the surgical literature. It may occur within hours to 3 weeks after CEA and is characterized by symptoms ranging from headaches, fits, confusion, focal neurological signs to intracerebral hemorrhage. Although percutaneous transluminal angioplasty (PTA) and stenting are increasingly performed as an alternative to CEA in the treatment of carotid artery stenosis, few cases of cerebral hyperperfusion injury following carotid stenting have been reported. We describe 2 cases of cerebral hyperperfusion syndrome following PTA and stenting for high-grade internal carotid artery (ICA) stenosis. Both cases involved a lesion of 95% in severity. The first case was a 73-year-old man who developed generalized convulsion 7 h following stenting to the left ICA. The second case was an 80-year-old woman who developed recurrent right periorbital headache and confusion 16 h after stenting to the right ICA, followed by left upper limb seizure 14 days later. Both patients fully recovered without any intracerebral hemorrhage or infarction. To our knowledge, this is the first report of cerebral hyperperfusion injury after carotid stenting without associated intracranial hemorrhage and with full recovery. In the patient with neurological symptoms following carotid stenting, it is important to consider cerebral hyperperfusion syndrome as a differential diagnosis to embolic or hemorrhagic stroke since early recognition and meticulous control of blood pressure may prevent progression to cerebral hemorrhage and death.

Hypertensive emergencies

A hypertensive emergency is a situation in which uncontrolled hypertension is associated with acute end-organ damage. Most patients presenting with hypertensive emergency have chronic hypertension, although the disorder can present in previously normotensive individuals, particularly when associated with pre-eclampsia or acute glomerulonephritis. The pathophysiological mechanisms causing acute hypertensive endothelial failure are complex and incompletely understood but probably involve disturbances of the renin-angiotensin-aldosterone system, loss of endogenous vasodilator mechanisms, upregulation of proinflammatory mediators including vascular cell adhesion molecules, and release of local vasoconstrictors such as endothelin 1. Magnetic resonance imaging has demonstrated a characteristic hypertensive posterior leucoencephalopathy syndrome predominantly causing oedema of the white matter of the parietal and occipital lobes; this syndrome is potentially reversible with appropriate prompt treatment. Generally, the therapeutic approach is dictated by the particular presentation and end-organ complications. Parenteral therapy is generally preferred, and strategies include use of sodium nitroprusside, beta-blockers, labetelol, or calcium-channel antagonists, magnesium for pre-eclampsia and eclampsia; and short-term parenteral anticonvulsants for seizures associated with encephalopathy. Novel therapies include the peripheral dopamine-receptor agonist, fenoldapam, and may include endothelin-1 antagonists.

Medical complications associated with carotid endarterectomy. North American Symptomatic Carotid Endarterectomy Trial (NASCET)

BACKGROUND AND PURPOSE

Carotid endarterectomy (CE) has been shown to be beneficial in patients with symptomatic high-grade (70% to 99%) internal carotid artery stenosis. To achieve this benefit, complications must be kept to a minimum. Complications not associated with the procedure itself, but related to medical conditions, have received little attention.

METHODS

Medical complications that occurred within 30 days after CE were recorded in 1415 patients with symptomatic stenosis (30% to 99%) of the internal carotid artery. They were compared with 1433 patients who received medical care alone. All patients were in the North American Symptomatic Carotid Endarterectomy Trial (NASCET).

RESULTS

One hundred fifteen patients (8.1%) had 142 medical complications: 14 (1%) myocardial infarctions, 101 (7.1%) other cardiovascular disorders, 11 (0.8%) respiratory complications, 6 (0.4%) transient confusions, and 10 (0.7%) other complications. Of the 142 complications, 69.7% were of short duration, and only 26.8% prolonged hospitalization. Five patients died: 3 from myocardial infarction and 2 suddenly. Medically treated patients experienced similar complications with one third the frequency. Endarterectomy was approximately 1.5 times more likely to trigger medical complications in patients with a history of myocardial infarction, angina, or hypertension (P<0.05).

CONCLUSIONS

Perioperative medical complications were observed in slightly fewer than 1 of every 10 patients who underwent CE. The majority of these complications completely resolved. Most complications were cardiovascular and occurred in patients with 1 or more cardiovascular risk factors. In this selected population, the occurrence of perioperative myocardial infarction was uncommon.

Imaging developing brain infarction

Continued advances in neuroimaging technology have made it practical to image multiple aspects of evolving brain infarction during the potential window period of therapeutic opportunity in stroke. Recent methodologic developments include computed tomography angiography and perfusion, and the description of quantitative parameters for magnetic resonance blood oxygen level-dependent perfusion imaging. In pathophysiologic studies, metabolism and function in the ischemic focus and the peri-infarct tissue have been further characterized. Clinical studies have focused on the applications of computed tomography and magnetic resonance imaging for prethrombolysis patient selection. These methods have an important role in the evaluation and development of new pharmaceutical agents and will be increasingly used in clinical practice as new therapies become available.